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Coniston Limestone is the sedimentary rock formation around Coniston in the English Lake District, and forms part of the Windermere Supergroup. It is late Ordovician or possibly early Silurian in age and rests unconformably upon the Borrowdale Volcanic Group of rocks, which subsided beneath the sea, after the volcanic period. Since the seas that gave rise to these deposits were teeming with life, there are fossils. Slowly the sea deepened and, over a long period, muds and sands were deposited. These are the Windermere Group sediments that are also of great thickness. Due to the collision of two tectonic plates, some 420 million years ago, the rocks have been intensely heated and squeezed. They have also been uplifted and now the once horizontal beds dip roughly south east at up to 90 degrees. This means that, progressing up the Coppermines Valley, the rocks become older. ==See also== *List of types of limestone 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Coniston Limestone」の詳細全文を読む スポンサード リンク
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